CODEWITHSUNDEEP
cprintfscanf
YoarkYANG
YoarkYANG

Reputation: 303

How to fscanf from a .csv which is a output of fprintf

I want to fscanf a csv file which is a output of fprintf, I set the same format but it didn't work, which means when I use that function to fscanf the file I just made, it didn't succuss, even didn't get into the while-loop. So, how to modify it to make it work?

Below part of my code

part of fprintf

fp = fopen("Out.csv", "w");
fprintf(fp, "%99s,%d,%99s,%99s\n", current->group, current->id, current->name, 
                    current->address);

part of fscanf

fp = fopen("Out.csv", "r");
while (fscanf(fp, "%99s,%d,%99s,%99s\n", group, &id, name, address) == 4) {
        head = push_sort(head, group, name, id, address);
        printf("%99s", name);
}

Upvotes: 0

Views: 1155

Answers (1)

Iharob Al Asimi
Iharob Al Asimi

Reputation: 53006

I suspect it's because "%s" specifier in *scanf() family stops scanning when it finds a white space, you can tell fscanf() which specific character to ignore, and it will stop at that character.

I believe the following format string will work

"%99[^,],%d,%99[^,],%99[^,\n]\n"

read this link to find out why I think the pattern will work, search specifically for the [ specifier.

The *scanf() functions are hard, it's always difficult to make them work correctly, although if you are generating the line and you're sure of what it contains and no surprises will happen, you can trust it to work.

You will be safe if you check the return value, which you do, so if you fail to read lines that you consider valid, then you can try to fgets() a line from the file, and parse it with strchr() or strtok(), I prefer strchr() because

  1. It doesn't need to alter the input string.
  2. It's thread safe and reentrant.
  3. It allows you to infere more, like the length of the token, without strlen().

Upvotes: 1

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